An adhesion promoter comprises a reaction product of: a) a polyepoxide; b) an aminosilane represented by the formula HNR1R2. R1 and R2 independently represent —Z—SiL3. Each Z independently represents a divalent linking group having from 1 to 12 carbon atoms, and each L independently represents a hydrolyzable group; and c) an isocyanatosilane represented by the formula O═C═N—Z—SiL3, wherein Z and L are as previously defined. The adhesion promoter may be used to treat a surface of a substrate such as an abrasive particle, which may be included in a resin-bond abrasive article.